(CNS) Central nervous system: In vertebrates (animals with backbones) this consists of the brain and the spinal chord only. In mammals, the CNS is connected to the body by sensory neurones and motor neurones
The (CNS) Central Nervous System coordinates the response
The CNS is a coordination centre - it receives information from the receptors and then coordinates a response. The response is carried out by effectors
CNS e.g 1. A small bird is eating some seed when, out of the corner of its eye, it spots a cat skulking towards it (the stimulus)
CNS e.g 2. The receptors in the bird's eye are stimulated. Sensory neurones carry the information from the receptors to the CNS
CNS e.g 3. The CNS decides what to do about it
CNS e.g 4. The CNS sends information to the muscles in the bird's wings (the effectors) along the motor neurones.
CNS e.g 5. The wing muscles contract and the bird flies away to safety